This invention relates generally to combustors and, more particularly to a method and apparatus for decreasing combustor acoustics.
At least some known gas turbine engines include a compressor for compressing air which is suitably mixed with a fuel and channeled to a combustor wherein the mixture is ignited for generating hot combustion gases. At least some known combustors include a dome assembly, a cowling, and inner and outer liners to channel the combustion gases to a turbine, which extracts energy from the combustion gases for powering the compressor, as well as producing useful work to propel an aircraft in flight or to power a load, such as an electrical generator. The liners are coupled to the dome assembly with the cowling, and extend downstream from the cowling to define the combustion chamber. An outer support is coupled radially outward from the outer liner such that an outer cooling passage is defined radially outward from the outer liner, and an inner support is coupled radially inward from the inner liner such that an inner cooling passage is defined therebetween.
At least some known liners include a plurality of panels that are serially connected together between the upstream and aft ends of each liner such that the panels define the combustion chamber. Because the panels are exposed to high operating temperatures generated within the combustion chamber, cooling air is channeled through the cooling passages to facilitate reducing the operating temperature of the panels. Specifically, such panels rely on backside convection cooling from the cooling passage flow, as well as hot-side film cooling, to facilitate enhancing extending the useful life of the panels. However, because the aft most panel is radially inward and downstream from the outer support, the aft most panel generally receives significantly less convective cooling air than other liner panels because the outer support directs the cooling downstream through turbine cooling feed windows. Over time, the reduced cooling of the aft panel may cause the aft panel to exceed predetermined operating limits established to facilitate optimizing the useful life of the liner.